2001 Honda Accord Engine over heating and car sputtering on

Engine Cooling problem
2001 Honda Accord 4 cyl Automatic 125000 miles

The engine over heats due to losing coolant from somewhere. I can't find a leak anywhere. The oil looks fine when looking at the dip stick, so Im unsure if coolant is getting in the engine. I had a coolant flush seemed to fix the problem for about 2 months but the same problem came back. I also had a check engine light come on because of a misfire in cyl 1, 2. I replaced all the spark plugs, spark plug wires, and distributer cap. Car ran fine for 1month, now the Car sputters again on start up and is fine when we drive on the highway and streets, it just overheats driving or on the stand still and am always low/losing coolant.